Heretofore, when a plurality of programs or reproduction video images have been viewed concurrently on a plurality of screens (display devices), the amount of information that can be obtained within a unit of time has generally varied in the individual programs or reproduction video images, thereby causing a deviation of information among screens. Considering efficiency of obtaining information, presenting an equal amount of information on each screen enhances the efficiency of obtaining information and convenience for users, and thus is more desirable. In a case of making information amounts uniform among programs displayed on respective screens, the information amounts can be matched to one another by respectively adjusting the reproduction speeds of the programs.
For example, in Japanese Unexamined Patent Application Publication No. 10-243351 issued by the Japan Patent Office, a technique is proposed in which video image features are detected in a video image containing moving images and sound and the video image is reproduced while the reproduction speed is being automatically adjusted in accordance with the video image features.
However, in general, since the information amount of a program or a reproduction video image is significantly affected by a standard of value of a recipient, it is difficult to determine the information amount by mechanical determination alone to change the reproduction speed.
For example, it has been considered that, by using a measurement device, such as, those of an electroencephalograph, an electrocardiogram, or NIRS (Near-Infrared Spectroscopy), an internal state of a viewer can be estimated on the basis of obtained waveforms or data to change the reproduction speed of a program or a reproduction video image. However, since a method that uses such a measurement device requires a large apparatus, a burden on a user (viewer) is increased and thus it is difficult to use such a method as measurement means on a daily basis. In addition, since it is expensive to provide a measurement device such as those mentioned above, ordinary viewers cannot make use of the device.
Further, as in the abovementioned method using a measurement device, in a case where an internal state of a viewer is estimated by using a response of the body of the user made when an object of interest such as a video image is presented, various factors may cause bodily responses, and thus it is difficult to specify the causes of the bodily responses and specify an internal state of the user.
Furthermore, in a case where an internal state of a user is attempted to be estimated by using a method that does not place the user under constraints in order to reduce a burden on the user, it is difficult to obtain a desired response of the user.
The present invention is provided in view of the above-described problems. It is an object of the present invention to adjust the content or amount of information to be presented on each screen on the basis of an involuntary response provided by a user with fewer burdens on the user.